Existing standards for optical discs allow a single boot format on one disc. A typical dual layer disc uses maps the address space of the second layer contiguous to the end of the first layer. A single boot sequence, starting on the inside of the first layer, mounts both layers. The layer transition is typically transparent to an application.
The existing mapping of the second layer is quite suitable for generic applications. Possibilities for rigorous application optimizations, however, are limited. A single disc has typically been optimized for generic use. A single disc suitable for both generic and application specific use turns out to be difficult to realize and is not very practical in usage. For one, an application specific use of a disc is difficult, as it first has to follow generic use conventions before proceeding to the application specific usage. This will cause a costly overhead in the specific application. Also this may cause the specific application to spend quite some time on performing tasks that are of no or limited relevance to the specific application.